Question on ride height street vs track

[Bob Winn]

Can anyone give me an idea of what ride heights people are using on street vs track?

I have read a variety of threads and it seems a lot of people are running 4-4.5" front / 4.7-5.25" rear on the street. Manual is 4"/4.5" ideal. Is that ideal for track, and we compromise for the street? 4" seems awful low for some (most? all?) of the streets in the Northeast. Are people setting the suspension to 4" and then driving around ramlifted to 5 or 5.5, until they get to decent roads? If so how does the lift effect the drive?

I have read a few threads talking about track setups, one talking about needing a sub 3" jack to use on their track car. I'm sure the heights for the factory track cars is known. I understand a lot of the height settings is going to depend on tires and spring rates, but I'm interested to know how low people take these things with success, and how they actually drive them on the street.

Thanks

Bob

 

[Mike Pass]

I have used 4" front and 4.5" rear chassis to ground for a long time. I have zillions of speed bumps near me but manage OK. I usually run one wheel about 3/4 the way across the speed bump. You still occasionally come across one with the wrong profile or illegally high which gives a jolt but it doesn't ground out.
I have run on tracks a few times (Le Mans, Donnington, Oulton Park) but not worth changing the ride height for - so just stiffen up the shocks a few notches. The issue with changing the ride height is that if you don't have corner weight scales you don't know where you are and can end up with the four legged stool with the diagonal legs too long. I have never checked to see if lowering the car by a couple of inches has a negative effect on the roll centres.
Because in the GT40 with no passenger the weight distribution is unbalanced I try to fill the left hand tank and have little in the driver's side to try to even things up.
There is a way to get the best corner weights sorted for an unevenly loaded car but probably not worth bothering with for a softly sprung car like a road GT40.
Cheers
Mike